The present invention relates to a device to be arranged between a gate and a powered drive to allow their release in case of need.
Release devices to be arranged under the wing of a gate and comprising a manually operated bolt for separating the geared wing-moving motor from the wing to permit manual movement of the wing in case of need are known.
To avoid undue use of these devices they are usually equipped with a key lock which must be operated to allow release. There have been proposed devices in which the lock acts positively to release the bolt. In these devices by operating the lock a bolt stop rocker arm is freed so that the interaction of appropriate inclined planes permits free backing of the bolt when the gate is moved manually. Another cam means resets the bolt for the next snap engagement once the lock in locked position is operated again.
Similar devices are relatively complicated and jam easily. As retraction of the bolt is caused only by interaction of the bolt with an inclined plane delimiting its engagement seat it is not possible to manually exert enough force to release it if the mechanism which usually holds the bolt in engaged position jams. Since the device must be arranged near the ground in a poorly protected position and as its operation is very occasional, foreign bodies, mud, dirt and water can lead in time with high probability to jamming of the entire mechanism with no possibility of forced release in case of need.
In addition the movement stress transmitted to the gate by powered operation is partially transmitted to the lock with the risk of putting the mechanism out of commission and the need of having to provide strong hence costly locks. In case of breakage of the lock in open condition it is impossible to again engage the bolt and powered movement of the gate.
The general purpose of the present invention is to obviate the above mentioned shortcomings by making available a device for manual release of a gate from its drive which would be simple, economical and reliable under all conditions.